This application is for an improved wall fastener that facilitates the process of clamping two adjoining surfaces together, such as to attach brackets or other objects to a hollow wall.
There are various wall fasteners in use. The one commonly used is the "toggle bolt." It employs anchor arms mounted with springs on a bolt or screw. The arms are compressed in a retracted position for insertion in a hole or aperture in a wall. After insertion the arms expand outward and, by turning the screw, the arms are pulled backwards against the wall or surface to which an object is to be attached. The shortcomings of the toggle bolt are that the arms, by expanding outward, cannot begin to open until the retracted arms are well clear of the backside of the wall. This can restrict the use of a toggle bolt when the arms must expand in a cavity formed by the space between two walls or surfaces. The arms cannot expand unless the width of the cavity exceeds the length of the arms. The device is also awkward to install because the bolt has to be grasped and be held firmly with one hand at the same time as it is being turned by the other.
A variation of the toggle bolt is the "molly bolt." Instead of arms the bolt has a shell surrounding it which is supposed to act as an anchor by collapsing against the wall when the bolt is turned. However, because significantly more force is required to collapse the shell than to just turn the bolt, the shell, rather than collapsing, tends to yield to this force as the bolt is turned by rotating ineffectually unless the shell is inserted firmly in material that is rigid enough to hold the shell in place or is held by some mechanical device. In addition, neither a toggle bolt nor a molly bolt can be removed once installed.